For in them is the spring of understanding, the fountain of wisdom, and the river of knowledge: It is not grammatically clear from the Latin whether the pronoun them refers to the seventy books or to the wise people, but from the context it is pretty clear that the books are intended. It is striking that the author thinks of the books reserved for the wise as of a higher order than the books of Scripture available to all. Three figurative expressions are used here to describe the seventy books: the spring of understanding, the fountain of wisdom, and the river of knowledge. These three phrases have basically the same meaning. All three are used to emphasize that the seventy books are filled with wisdom. The Latin words for spring and fountain both refer to a source of water coming up from the earth. Good News Bible may be used as a model for this verse. Contemporary English Version changes the metaphors into a simile as follows:

• These books are filled with understanding, wisdom, and knowledge that flow like streams of fresh water.”

Another possible model is:

• because these books contain springs and rivers of understanding, wisdom, and knowledge.”

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on 1-2 Esdras. (UBS Helps for Translators). Miami: UBS, 2019. For this and other handbooks for translators see here.